The present invention generally relates to filters used in audio applications and more particularly to filters designed to allow for accurate loudspeaker system equalization.
There are two standard equalization devices used for loudspeaker equalization. “Graphic” equalization devices are used to alter the tonal balance of program material (music, speech). Traditionally, these devices are comprised of a large number of second-order filters, and particularly octave band or one third octave band banks of fixed filters. Since the location of the center frequency of each filter is fixed, the frequency bands often do not correspond to the necessary bands for loudspeaker system equalization. Also, these fixed filters can interact poorly, creating phase distortion when adjacent bands are set incorrectly.
Banks of parametric filters are also used for loudspeaker equalization. Parametric filters are not fixed, however, in isolation, neither parametric nor graphic equalizers can create the filter shapes necessary for advanced loudspeaker equalization and setup.
The present invention provides a filtering system and method for equalizing loudspeaker systems that improves on the ability to create a wide variety of filter shapes to address a wide variety of equalization needs and challenges. The present invention provides a filtering system and method that minimizes the phase distortion associated with high order filters, while providing the filter shapes necessary to equalize arrays of flat frequency response loudspeakers in resonant acoustic environments.